Abstract: A power supply circuit for powering first and second groups of hard disk drives in a cabinet, includes a connector and first to third connection units. When there is only one server in the cabinet, the first node is connected to the first power terminal of the connector, the first connection unit is turned on, and the second connection unit is turned off. When there are two servers in the cabinet, the first and second nodes are respectively connected to the first and second power terminals of the connector, the first connection unit is turned on, and the second and third connection units are turned off.

Abstract: Disclosed is a method for managing a defect of an optical disc. In the method, when a host requests data of an optical disc inserted into an optical disc drive (ODD) included in a device to be integrated with a solid state drive (SSD), an address of the requested data is compared with contents contained in defect management information managed within the SSD, and the requested data is read from the optical disc or from the defect management information according to a result of the comparing. The defect management information may include optical disc identification information, address information, defect type information and data of a corresponding address. When the optical disc is inserted into the ODD, defect management information regarding the optical disc may be generated and stored in the SSD. Accordingly, Read Delay or Read Fail, resulting from a defect of the optical disc, can be obviated.